Four-quadrant indicator employing moire effect

ABSTRACT

Display apparatus for indicating motion and displacement of a control lever movable about one end thereof through various positions within a spherical sector of radius substantially coextensive with the lever comprises a first regular pattern formed on a transparent surface positionable by the control lever, and a second regular pattern formed on a surface beneath the positionable surface. By employing equally spaced lines in each pattern, each position of the control lever results in creation of unique moire fringes which are set into motion whenever the control lever is moved.

United States Patent [1 1 Seager 1451 July 17, 1973 1 FOUR-QUADRANTINDICATOR EMPLOYING MOIRE EFFECT [75] lnventor: Richard H. Seager,Manlius, NY.

[73] Assignee: General Electric Company,

Syracuse, N.Y.

[22] Filed: Nov. 26, 1971 [21] Appl; No.: 202,369

[52] US. Cl 116/124, 40/l06.53, 40/137,

74/471, 338/128 [51 Int. Cl. G091 9/00 [58] Field of Search 116/114, 124R,

116/129 R;40/106.53,106.5,137,106.51; 338/128; 272/8 M; 250/237 G;356/169; 74/471 1 56] References Cited UNITED STATES PATENTS 2,917,85412/1959 Swarbrick 40/106.51 X 3,365,975 1/1968 Hathaway.... 338/128 X3,372,359 3/1968 Wilson 338/128 3,629,775 12/1971 Kindred 338/1283,634,959 1/1972 Goodrich 340/27 R Eaves..... 4()/l06.53

Komatsu 338/128 OTHER PUBLICATIONS Publication: Edmund ScientificCoBarrington, N. 1., Catalog 671, Cover-Page, Page 2, Pages 74 & 75.

Primary Examiner-Louis J. Capozi Attorney-Marvin Snyder et a1.

57 ABSTRACT 11 Claims, 6 Drawing Figures PAIENTLU JUL 1 mm SHEU 1 BF 3FIGS PAIENIED JUL 1 7 ms SHEU 3 BF 3 RIGHT- FIG.6

FRON

RE'AR --ILEFT- FOUR-QUADRANT INDICATOR EMPLOYING MOIRE EFFECTINTRODUCTION This invention relates to visual displays, and moreparticularly to indicators for displaying the effects of moving acontrol lever about one end thereof through various positions within asubstantially spherical sector of radius coextensive with the lever.

The purpose of employing four-channel stereo playback systems is toreproduce for the listener the effect of hearing music as he might if hewere seated at a live performance in a concert hall, wherein he hearssound emanating directly from the stage and reverberating from thesurfaces within the hall. As the name implies, four separate channels ofsound are involved, with each channel representing the sound at aparticular location at the recording site. These channels areindividually coupled through the system to four separate loudspeakerenclosures, two of which are preferably placed in front of the listeneron either side thereof and reproduce the sound recorded at the left andright sides of the stage, and the other two of which are preferablyplaced behind the listener on either side thereof and reproduce thecomplex sound at the rear of the hall made up of natural reverberationsfrom the surfaces within the room containing the recording site plussound emanating from the stage itself.

In order to provide the listener with reproduced sound that seemingly ishow he would have heard it if present in the concert hall when and whereit was produced, it is necessary to balance the system so that volume ofsound produced by the system is optimized. This balance obtains when thevolume of sound produced by any one loudspeaker enclosure is relativelythe same, with respect to that produced by each of the other threeloudspeaker enclosures, as the volume of sound recorded at the recordinglocation corresponding to that one enclosure is with respect to thevolume of sound recorded at each of the other three recording locations,respectively. One type of control for achieving such balance hasrequired use of three separate potentiometers. Typically, in this typeof control, one potentiometer balances the right front and left frontloudspeaker enclosures with respect to each other, the second balancesthe left rear and right rear loudspeaker enclosures with respect to eachother, and the third balances the combined front loudspeaker enclosureswith respect to the combined rear loudspeaker enclosures. While suchcontrols are entirely adequate, they require individual manipulation ofthree separate knobs.

To reduce the manipulations required to achieve balance among separateloudspeaker enclosures in fourchannel stereo playback systems, aso-called joystick control has been employed. This control operates in amanner similar to that of the control stick employed in aircraft toachieve changes in pitch and roll; that is, movement of the joystickthrough any geometric plane oriented along a given direction controlsaudio output of the pair of front loudspeaker enclosures in relation tothe pair of rear loudspeaker enclosures, and movement of the joystickthrough any geometric plane oriented along a direction perpendicular tothe given direction controls audio output of the pair of loudspeakerenclosures on the left in relation to the pair of loudspeaker enclosureson the right. Movement of the joystick in any direction other thanthrough the aforementioned geometric planes causes interaction among theaudio outputs of the four loudspeaker enclosures with the resultanteffect being that a complete rebalancing of the audio outputs producedby all four loudspeaker enclosures occurs.

Small displacements of the joystick control, however, may not have areadily noticeable effect on the audio outputs of the loudspeakerenclosures, due, for example, to the degree of aural sensitivity on thepart of the listener (especially if the displacement is made at theinstant when the musical instruments in one section of the orchestralmusic source substantially supplant the musical instruments in anothersection). In such case, the listener may not be sure that he did, infact, reposition the joystick. Accordingly, one object of the inventionis to provide an indicator on which displacement of the joystick by evena small amount may be visually detected.

Another object of the invention is to provide a device which presents amoving visual display during movement of a joystick.

Another object is to provide esthetic visual effects to accompany eachmovement of a joystick and a different esthetic visual pattern toaccompany each separate respective position of the joystick.

Another object is to provide apparatus employing the moire effect todesignate the general direction in which a joystick is moved.

Briefly, in accordance with a preferred embodiment of the invention, avisual display for indicating motion and dsiplacement of a control levermovable about one end thereof through various positions within aspherical sector of radius substantially coextensive with the lever isprovided. The display comprises a first regular pattern formed on atransparent surface which is positionable by movement of the lever, anda second regular pattern formed on a surface situated beneath thetransparent surface such that the second regular pattern is visiblethrough the transparent surface. The first and second patterns are thussuperimposed on each other so as to form moire fringes.

BRIEF DESCRIPTION OF THE DRAWINGS The features of the invention believedto be novel are set forth with particularity in the appended claims. Theinvention itself, however, both as to organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference -to the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a side view of the indicator of the present invention;

FIG. 2 is a plan view of a typical stationary pattern employed in theindicator of the invention;

FIG. 3 is a plan view of a movable pattern employed in the indicator ofthe present invention;

FIG. 4 is a plan view of a typical viewing window employed in theindicator of the invention;

FIG. 5 is a top view of the indicator of the present in vention, withthe joystick in its center position; and

FIG. 6 is a top view of the indicator of the present invention, with thejoystick offset from its center position.

DESCRIPTION OF TYPICAL EMBODIMENTS In FIG. 1, the indicator of thepresent invention is illustrated as comprising an escutcheon 10 and ajoystick 11 having a manually operable portion 9 thereof, which swivelsat one end about a ball and socket joint made up of ball 12 and socketl3. Joystick 11 is thereby movable through various positions within aspherical sector of radius substantially coextensive with joystick 11. Arod 14, affixed to ball 12, penetrates gimbals l and 16 so as to movethe gimbals whenever ball 12 is repositioned by movement of joystick 11.

A group of four potentiometers, two of which, 17 and 18, areillustrated, are mounted on each side of a foursided chassis 20, shownpartially cut away, such that each potentiometer shaft, such as shaft21, is affixed to one end of a gimbal, respectively. Thus, potentiometershaft 21 is affixed to one end of gimbal 16 while poten tiometer shaft22 is affixed to one end of gimbal l5, and movement of joystick 11 isconveniently converted into rotation of the potentiometer shafts. Eachpotentiometer is electrically connected to control amplitude of audiooutput from a separate loudspeaker enclosure, respectively.

Affixed to chassis is an apertured plate on which, as shown in FIG. 2, aregular, distinctive pattern is formed by any of a number ofconventional ways, such as printing, engraving, overlaying, etc. Thispattern preferably comprises a plurality of equidistantly spaced linesso as to constitute a periodic strucure, formed on the upper surface ofplate 30. Conveniently, the pattern may be made up of four sets of arcsof concentric circles, each set of arcs, respectively, being centeredabout a separate comer of plate 30 where plate 30 is formed in the shapeof a four-sided polygon, such as a square. Joystick 11, as shown in FIG.1, passes through the aperture in plate 30, leaving the joystick free toswivel within the aperture.

Positioned atop plate 30, as shown in FIG. 1, is a transparent plate 31having a sloped collar 32 with a beveled edge 33 facing joystick 11.Plate 31 is slidably displaceable through 360 within the plane of theplate. Joystick 11, when moved, bears against collar 32 so as to shiftthe position of plate 31 in the direction of movement of the joystick.Any portion of beveled edge 33 cooperates with its diametricallyopposite portion of the inner surface of collar 32 to allow joystick 11,when thrown fully to one side, as illustrated by either dottedpositionof joystick 11, to minimize lost motion between the joystick andplate 31 when the joystick is returned from its maximum offcenterposition.

As illustrated in FIG. 3, plate 31,'typically in the shape of afour-sided polygon, such as a square, contains a regular, distinctivepattern made up of a plurality of equally spaced opaque lines so as toconstitute a periodic structure. Conveniently, the line pattern isformed of a plurality of concentric circles on the lower surface ofplate 31, with arcs of concentric circles extending outward to thecorners of the plate. The circles are centered about the center of theaperture defined by collar 32. Spacing of the lines in the pattern onplate 31 is made equal to that in the pattern on plate 30, in order toproduce well-defined, prominent moire fringes by virtue ofsuperimposition of the patterns on plates 31 and 30. As with plate 30,the line pattern produced in plate 31 may be formed by any of a numberof conventional methods, such as printing, engraving, overlaying, etc.An additional pattern 34, comprising an arrangement of dots andradially-directed lines situated in a circle, is preferably formed by asimilar process on the upper surface of plate 31 and centered about thecenter of the aperture therein, giving added visual emphasis to theposition of the joystick on the indicator.

Situated atop plate 31, as shown in FIG. 1, a fixedlymounted,transparent viewing plate 35 containging indica, such as illustrated inFIG. 4, to designate the effect of movement of the joystick in any.given direction. These indica, which show the user what loudspeakerenclosure or enclosures of the four-channel stereo system are beingemphasized and what enclosures are being deemphasized, generally signifyfour quadrants within which sound is emitted, permitting the listener tobalance the sound heard from these four quadrants as he desires. Theindicia may be formed by any of the aforementioned methods for producingpatterns on plates 30 and 31 of FIG. 1, on the lower surface of plate 35in order to prevent abrasion of the pattern through normal usage of theindicator. An opaque border 36 around plate 35 prevents the edges ofplate 31 from being visible to the user even when joystick 11 is at itsmaximum off-center position.

FIGS. 5 and 6 are illustrations of typical moire fringes presentedvisually to the user. In the example of FIG. 5, the joystick iscentered, so that circular scale 34 of dots and radial lines on theupper surface of plate 31 is centered about the joystick and withrespect to the indicia on the viewing plate. However, should thejoystick be moved from its central position, the moire fringe pattern isaltered and circular scale 34 moves off-center with respect to theindicia on the viewing plate, in the direction of displacement of thejoystick. This condition is illustrated in FIG. 6. During motion of thejoystick from its condition illustrated in FIG. 5 to its conditionillustrated in FIG. 6, the moire fringe pattern is altered, and a visualillusion of much movement is presented to the user of the indicator,even if thejoystick motion is slow and even if it is produced by but asmall displacement of the joystick. Hence, the user visually receivesinformation which unmistakeably tells him that he has moved thejoystick. Additionally, by use in the indicator of the patternsillustrated in FIGS. 2 and 3, movement of the joystick in any givendirection causes the moire fringes to appear to widen or open in thedirection toward which the joystick is being moved, and to narrow orclose behind the joystick, thereby providing to the user an indicationof the quadrant toward which the joystick is being moved. To furtherenhance the visual effects, plate 30 of FIG. 1 may be made transparent,and a light source employed beneath plate 30, so that the opaque linesforming the patterns on plates 30 and 31 produce directly illuminatedmoire effects.

The foregoing describes an indicator on which displacement of ajoystickby even a small amount may be visually detected. The device providesesthetic dynamic visual effects to accompany each movement of thejoystick and different esthetic static visual patterns to accompany eachseparate respective position of the joystick. The moire effect isemployed to produce fringes designating the general direction in whichthe joystick is moved.

While only certain preferred features of the invention have been shownby way of illustration, many modifications and changes will occur tothose skilled in the art. It is, therefore, to be understood that theappended claims are intended to cover all such modifications and changesas fall within the true spirit of the invention.

I claim:

1. Display apparatus for indicating motion and displacement of a controllever movable about one end thereof through various positions within aspherical sector of radius substantially coextensive with said lever,said apparatus comprising:

a first regular pattern formed on a transparent surface, saidtransparent surface being engageable with said lever and displaceablethrough 360 by movement of said lever;

a second regular pattern formed on a surface situated beneath saidtransparent surface such that the second regular pattern is visiblethrough the transparent surface, said first and second patterns beingsuperimposed on each other so as to form moire fringes; and

means retaining both of said surfaces to limit maximum displacement ofsaid first pattern relative to said second pattern.

2. The display apparatus of claim 1 wherein said transparent surfacecontains an aperture through which said lever passes to permit saidtransparent surface to be slidably displaced atop the surface on whichsaid second pattern is formed, in accordance with the positioning ofsaid lever.

3. The display apparatus of claim 2 wherein said aperture is surroundedby a collar, said collar being in contact with said lever at least whensaid lever is being moved.

4. The display apparatus of claim 1 wherein the surface on which saidsecond pattern is formed is transparent.

5. The display apparatus of claim 1 wherein the surface on which saidsecond pattern is formed is opaque.

6. The display apparatus of claim 2 wherein each of said first andsecond patterns comprises substantially equally spaced lines, each ofsaid lines representing at least an arc of a circle.

7. The display apparatus of claim 6 wherein lines in said first patternform a plurality of concentric circles and lines in said second patternform four sets of arcs of concentric circles, each set of arcs,respectively, in said second pattern being centered about a separatecorner ofa four-sided polygon, respectively, containing said secondpattern.

8. A visual display for indicating motion and displacement of a levermovable about one end thereof, said lever being displaceable through aspherical sector of radius substantially coextensive with said lever,said display comprising:

a first pattern of equally spaced lines being formed of opaque materialseparated by regions transparent to light, said lever being contiguousto said first pattern such that said first pattern is displaceablethrough 360 by movement of said lever;

a second pattern of equally spaced lines being formed of oapque materialseparated by regions transparent to light, said first and secondpatterns being superimposed on each other to form moire fringes; and

means retaining both of said patterns to limit maximum displacement ofsaid first pattern relative to said second pattern.

9. The visual display of claim 1 whrein said first pattern includes anaperture through which said lever passes to permit said first pattern tobe slidably displaced atop said second pattern in accordance withpositioning of said lever.

10. The visual display of claim 9 wherein the line spacing of said firstpattern equals the line spacing of said second pattern, each of saidlines being at least an arc of a circle.

11. The visual display of claim 10 wherein lines in said first patternform a plurality of concentric circles and lines in said second patternform four sets of arcs of concentric circles, each set of arcs,respectively, being centered about a separate corner of a four-sidedpolygon, respectively, containing said second pattern.

1. Display apparatus for indicating motion and displacement of a controllever movable about one end thereof through various positions within aspherical sector of radius substantially coextensive with said lever,said apparatus comprising: a first regular pattern formed on atransparent surface, said transparent surface being engageable with saidlever and displaceable through 360* by movement of said lever; a secondregular pattern formed on a surface situated beneath said transparentsurface such that the second regular pattern is visible through thetransparent surface, said first and second patterns being superimposedon each other so as to form moire fringes; and means retaining both ofsaid surfaces to limit maximum displacement of said first patternrelative to said second pattern.
 2. The display apparatus of claim 1wherein said transparent surface contains an aperture through which saidlever passes to permit said transparent surface to be slidably displacedatop the surface on which said second pattern is formed, in accordancewith the positioning of said lever.
 3. The display apparatus of claim 2wherein said aperture is surrounded by a collar, said collar being incontact with said lever at least when said lever is being moved.
 4. Thedisplay apparatus of claim 1 wherein the surface on which said secondpattern is formed is transparent.
 5. The display apparatus of claim 1wherein the surface on which said second pattern is formed is opaque. 6.The display apparatus of claim 2 wherein each of said first and secondpatterns comprises substantially equally spaced lines, each of saidlines representing at least an arc of a circle.
 7. The display apparatusof claim 6 wherein lines in said first pattern form a plurality ofconcentric circles and lines in said second pattern form four sets ofarcs of concentric circles, each set of arcs, respectively, in saidsecond pattern being centered about a separate corner of a four-sidedpolygon, respectively, containing said second pattern.
 8. A visualdisplay for indicating motion and displacement of a lever movable aboutone end thereof, said lever being displaceable through a sphericalsector of radius substantially coextensive with said lever, said displaycomprising: a first pattern of equally spaced lines being formed ofopaque material separated by regions transparent to light, said leverbeing contiguous to said first pattern such that said first pattern isdisplaceable through 360* by movement of said lever; a second pattern ofequally spaced lines being formed of oapque material separated byregions transparent to light, said first and second patterns beingsuperimposed on each other to form moire fringes; and means retainingboth of said patterns to limit maximum displacement of said firstpattern relative to said second pattern.
 9. The visual display of claim1 whrein said first pattern includes an aperture through which saidlever passes to permit said first pattern to be slidably displaced atopsaid second pattern in accordance with positioning of said lever. 10.The visual display of claim 9 wherein the line spacing of said firstpattern equals the line spacing of said second pattern, each of saidlines being at least an arc of a circle.
 11. The visual display of claim10 wherein lines in said first pattern form a plurality of concentriccircles and lines in said second pattern form four sets of arcs ofconcentric circles, each set of arcs, respectively, being centered abouta separate corner of a four-sided polygon, respectively, containing saidsecond pattern.